


The Halfing of the Red Flames

by ObessedWithAdamWadeGontier



Category: Ao no Exorcist | Blue Exorcist
Genre: Banter, Childhood Memories, F/M, Flirting, Friendship, Half-Sibling Incest, Male-Female Friendship, Memories, Multi, Oral Sex, Possessive Behavior, Romance, Sexual Tension, Threesome
Language: English
Status: In-Progress
Published: 2015-01-05
Updated: 2015-01-06
Packaged: 2018-03-05 13:17:40
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 3,611
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3121598
Author URL: https://archiveofourown.org/users/ObessedWithAdamWadeGontier/pseuds/ObessedWithAdamWadeGontier
Summary: <blockquote class="userstuff">
              <p>Mephisto & Amaimon meet another half-demon that has caught their father's attention; Cheshire. A sixteen year old demon with the same sword as Rin, & looking for him to help slay Satan.</p><p>Mephisto finds himself vexed by this flimsy demon & slowly falls for her courage, & endurance. But there's a big problem for Mephisto & he's not sure she'd dare date him. Cheshire; she's his half-sister...</p><p>Amaimon is intrigued with the powers of their newest sibling much like Rin's, & is curious to see the aftermath of a battle between the two.</p><p>Cheshire. Very opinionated, & follows her own code; blood before anything. She knows of Rin's & Yukio's location, always passing them by but never speaking to them. She questions why she continued following them. She came to help him defeat Satan right? Cheshire sometimes doubts that's why she actually came to find Rin & Yukio.</p>
            </blockquote>





	1. We Are Family

Cheshire lifted her head slowly, her chin length hair filing out of her eyes only to be blinded by bright lights. She hissed & tried shielding her eyes from the rays only to realize they were chained behind her to the floor, her brown eyes widened & she began to panic, pulling at the chains to no prevail.

 _How'd I get here? I was just with the other at school! Wait, where's my sword?!_ Cheshire was more afraid of her last thought as she realized her black sword sheath wasn't strapped to her back.

A low chuckle sounded from in front of her, "Looking for this?" A tall male stepped into the light, his hair a deep purple with a single strand standing up atop his head, eyes a vibrant green, & a sly grin on his face as he held up the sword. It no longer in it's clothed sheath, but it's normal sheath that hid the blade beneath. Cheshire mentally sighed in relief, she never worried about it so much but she was glad to see the lovely black hilt, & gold scroll work decorating it.

"Where am I?" Cheshire asked the grinning male.

"Amaimon, please, come. We have a guest, one I'd think you'd much enjoy getting to know." He said.

 _Amaimon? That name- it's so familiar._ She thought narrowing her eyes as a smaller, green haired boy fell from the ceiling. His ripped cape fanning out around him as he stared with a blank expression at Cheshire.

"Mmm," he cocked his head to the side, "what's her name Mephisto?" He asked before turning to the other. Cheshire quietly gasped at realization of who the green haired boy was, the King of Earth, one of eight demon kings.

"Even I haven't the slightest clue." The man, Mephisto shrugged, "Father said we would want to meet her."

"My names Cheshire, now why exactly am I here? Not to mention where am I, & can I have back my sword?" Cheshire asked boldly, causing both to look at her. Mephisto smiled & took his time to walk to her, Amaimon followed his brother, coming to stop in front of her.

"Why would I give you back your weapon?" Mephisto asked, tilting her head up with a finger hooked beneath her chin. Cheshire bared she sharpened fangs at him, slightly pointed ears laying flat.

"Because, that's a demon killing sword, my Kurikara, it's dear to me because it holds my powers." Cheshire said without care.

"Here," Mephisto tossed the sword to Amaimon who's calm expression morphed into a devilish one, he unsheathed the sword & red flames engulfed both it & Cheshire. Red flames made horn-like figures sprout from her ink, black hair, & a black tail appeared at her side, red flames at the tip. Cheshire glared at them, ears pointed & teeth razor sharp.

"Can you please not-"

"She's a lovely specimen if I may say brother." Amaimon said with a slight smile, "Oh, look! Her eyes are burning with much anger, I wonder just how strong she is. Don't you dear brother?"

Mephisto nodded, "Indeed. Father however, told us to be weary of this one..." He said, "... more weary than with Rin." Mephisto added as he glanced over at his brother before kneeling in front of the teen demon, "So, tell me- no! Show me, us, just what makes you so important to our father." Mephisto said in a challenging way.

Cheshire lifted her head, revealing a malicious grin, "You asked for it." She tugged at her restraints, slowly pulling them out the ground. Both brothers backed away as the red flames morphed to a deep purple, then a vibrant blue. Cheshire laughed manically as black tribal markings appeared on her arms, & neck, eyes glowing an ungodly silver as she hissed at Mephisto & Amaimon.

"You're...?" Amaimon began as he sheathed the sword, but alas the sixteen year olds flame didn't dim in the slightest.

 _"A child of Satan."_ Mephisto seemed to purr delightedly. "Welcome then sister." He said leisurely bowing, "We have very much to discuss." Cheshire rolled her eyes, flames dissipating as she walked over to Amaimon, snatching back her sword,  & throwing it onto her back.

"Leave me alone... _brothers_. I needn't time for your games, I must go speak with the Rin boy. After all, our swords are two of a kind,  & together they're unstoppable." Cheshire said with a wide smile. Mephisto looked to his younger brother, handing him money.

"Go buy yourself some candy." He stated & Amaimon didn't reply, he merely teleported out the room. Mephisto looked to the metal door, smirking at the fist shaped hole in it. "Aw," he chuckled, "this one will be even more fun to toy with than Rin as well." Mephisto said to himself, twirling his umbrella as he followed the same path his half-sister had just taken.


	2. Times Two Shame On You Times Three Shame On Me

**Summary for the Chapter:**

> "This is the third time in these past five days!" Cheshire said glaring down at the navy blue haired boy, & green haired demon. "Amaimon, you're not gonna win!" She shouted down at him.

_One_

"Rin, don't!" Yukio yelled as his brother drew his sword, bursting into a blinding blast of blue light. The flames engulfing him as he held the blade in both hands, snarling as he charged the green haired male.

"... Didn't you say Amaimon lost to him already?" Cheshire asked, one arm resting atop her knee while her other leg dangled. Mephisto looked up at her as she sat on the arm of his floating chair, watching with bored brown eyes as the two demons fought below.

He sipped his tea, "Indeed. But like all children... They absolutely _hate_ losing, Amaimon is no exception." Mephisto continued watching her from the corner of his eye, noticing she didn't move much, her tail laying on the back of the chair, red flames dim at the tip of the black, velvety tail.

"How do you watch this?" Cheshire asked ten minutes into the fight, chin resting on her palm.

Mephisto chuckled, "You don't find the show pleasurable?" She huffed, looking at him.

"Fuck no. This is boring." Cheshire said drawing her own sword, deep red flames circling her as she spouted stone gray feather wings, & flew off. Mephisto's eyes stayed on her until she was so far into the night he could no longer see her, closing his eyes briefly as he smirked.

 _Cheshire... There's something about you. But what?_ He opened his eyes, snapping his fingers, making his chair  & tea vanish. He hovered down to Amaimon who hung upside down in a tree, Rin running at them both with a deadly intent.

"Come brother, enough fighting for today, time for rest." Rin sliced the air where'd they just been, snarling in anger.

_Two_

The twitch in Cheshire's eye went unnoticed, "Again?" She questioned before face palming. Mephisto smirked to himself as he watched the two relatives fight once more.

"Amaimon isn't happy he lost twice already." He said as Amaimon came flying in their direction. Both parted, allowing him to sail past them into a river.

"I must say Rin is strong, being able to take on a full demon when he is merely half himself." Cheshire said with an interested tone. Mephisto nodded & made a jar of candy appear, "You two piss me off with that."

Mephisto raised a questioning brow, "What?" He asked sticking the sucker into his mouth. Cheshire gestured to the bowl of candy.

"That. Using your powers to make candy appear," she said looking back to the fight. "Uh, Amaimon is being drowned by the Rin boy." Cheshire said pointing down below them. Mephisto looked down himself, seeing his brother being held underwater by Rin, who's flames seem to have grown quite out of hand.

"Rin! You need to calm down!" Yukio said running to his brother. Rin stopped immediately, calming down as his brother rested a hand on his shoulder.

"Shall I collect him or you?" Mephisto asked titling his head to look at the teen girl. Cheshire crossed her arms & huffed before flying off once more, "I'll take that as me."

_Three_

Cheshire threw up her arms, groaning as the two were at it again.

"This is the third time in these past five days!" Cheshire said glaring down at the navy blue haired boy, & green haired demon. "Amaimon, you're not gonna win!" She shouted down at him.

Amaimon stopped, looking up at his sister, "You don't believe I can win? How rude, doubting your older brother." He said flatly, teal eyes blank. They continued fighting & Mephisto tried distracting her from their fight.

"What's your favorite color?" Mephisto asked, hands toying with the necklace around her neck. Cheshire raised her brow & looked up at the 6'5 demon, finding his eyes quite transfixed on her face.

"I haven't time for this I'm quite bored & wish to return to my room." She said eyes flickering down to Amaimon as he was thrown backwards, Rin's sword narrowly missing his face.

"Well, no one's stopping you." Mephisto stated, carefully dragging his finger along her collarbone for a split second, Cheshire not noticing in the slightest.

"With my brothers." Cheshire said meeting his green gaze as she smacked away his hand. Mephisto grinned as she unsheathed her sword, the red flames bringing the attention of Amaimon, Rin, & Yukio.

"Who's that?" Rin asked no one in particular as the flaming girl landed between Amaimon, & him. Amaimon slowly sat up, still sitting on the ground as he smiled darkly.

 _Finally, these two will duke it out... Let us see who's stronger_. He thought watching as her tail swished fluidly behind her.

"I'm Cheshire, Satan's daughter. You're half-sister," she said holding tight to her Kurikara. Rin & Yukio both looked shocked.

"What? How, your flames! They're red!" Rin exclaimed.

Cheshire rolled her eyes as she moved to stand over her brother, "If you wish to live I suggest you leave my brother alone." She growled. Rin looked at her before baring his own fangs. Amaimon watched in glee as the two fought, flames mixing & making a lovely purple. Mephisto floated down to his brother.

"Come now, it's time to leave." Amaimon nodded & vanished, leaving Mephisto still there. Cheshire got the drop on Rin & aimed a well placed kick to his stomach, sending him flying through the forest, tearing up trees & smashing boulders. Mephisto jumped up elegantly, hand wrapped around the back of Cheshire's neck.

"... Mephisto...?" She murmured softly, head lulling back as her body succumbed to an almost lifeless state, mind falling into black. Mephisto picked her up bridal style, smiling down at her as she looked so peaceful. But he frowned seconds later, hating the scrapes & small cuts decorating her lovely face.

"Rest for now my dearest sister. Tomorrow you shall wake, & have a lovely time at the ball I've been invited to." He said teleporting to his room in True Cross Academy. Mephisto laid her down in his bed, pulling the covers over her, & gently kissing her forehead.


	3. Touch of Mephisto & Kiss of Amaimon

**Summary for the Chapter:**

> Mephisto & Cheshire ready for the party, but prior to them getting dressed Cheshire is out & about True Cross Academy, watching her half-brother Rin interact with the other students, his friends, & considers what her part would be if she had decided to join Cram herself.

**Notes for the Chapter:**

> Cheshire's Dress Mephisto handpicked for her >  
> http://fdqwholesale.co.uk/50s/222-black-halterneck-rockabilly-dress.html

Cheshire's eyes opened, she stretched, yawning quietly.

 _Where am I? This isn't my room_. She thought confusedly. Cheshire looked around the room, fingers gripping the sheets as she popped a few of her aching bones. She noticed the purple of the sheets, groaning quietly.

"Mephisto." She said softly, just now feeling a weight on her legs & pelvis. Cheshire peered down her covered body, finding Amaimon asleep on her, sucker poking out from between his slightly parted lips.

"Aw, you're awake. Morning Cheshire." Mephisto said popping his head through the door, smiling & showing off his pearly white fangs. She rolled her eyes & carefully shifted until able to sit up properly, sadly awakening Amaimon in the process. He looked drearily at her, teal eyes having more bags than the day before.

"Sorry Amaimon, I didn't mean to wake you." She said softly to him, running a hand through his hair to soothe him. Amaimon's eyes shut slowly & he rested his head on her leg, slowly drifting back to sleep. Mephisto watched as admiration shined in Cheshire's eyes, a small smile tugging at her lips as she continually stroked his hair.

"Are you hungry?" She shook her head & removed herself from the bed.

"Maybe later, for now I'm going to shower." Cheshire said with a catlike grin over her shoulder.

 

* * *

 

Cheshire finished washing the subs out of her hair, & off her skin before exiting the shower, wrapping a black towel around her body as she brushed her teeth.

"You look nice in my monogrammed towels." Mephisto purred as he leaned against the door, long arms crossed over his chest. Cheshire threw a bar of soap at him, getting him to move long enough for her to squeeze past.

"Screw off perv. We're blood." Cheshire said dropping her towel & snapping her clothes onto her. She glanced herself over, combat boots, army cargo pants, & a black guy's tank top.

"We're demons; sins in our blood." Mephisto said as he came closer, "And we're only half blood." He purred against her ear, forked tongue brushing the shell of her ear. Cheshire smacked his tongue away, & headed towards the door.

"You come on way too strong." She said over her shoulder.

Mephisto shrugged, "Demon, may I remind you." He added, "Oh, I've been invited to a small demon party, you could say. I need a date because I do not wish to be miserable alone."

She rested a hand on her hip, "Is Amaimon going?" His green eyes narrowed.

"Yes, there's candy, why wouldn't he go?" Mephisto said agitated. Cheshire pursed her lips before nodding.

"Then yes, & tell him to dress ravishingly. You as well," he raised a purple eyebrow, "I wish to make all the demons jealous." Mephisto grinned evilly, & held up his long fingered hand.

"Drei... zwei... eins!" A small white Terrie with a pink, white polka dotted bow replaced Mephisto. "See you at seven tonight my dear, I'll pick you out something that suits your curves." The dog seemed to smile before walking out the opened door.

 

* * *

 

Cheshire spent her day following around Rin, or Yukio... mainly Rin because he actually possessed a blade as powerful as hers.

 _He's quite handsome, I see why the little blonde girl adores him_. She thought as he argued with a boy that had a blonde streak in his hair, _But he is hardheaded & a loose cannon, no wonder the Vatican keeps a close eye on him._

"If I were to join cram as a student, I'd be a Tamer, with my yin & yang wolves, & a Knight because of my sword." She mumbled to herself. Cheshire sat down atop the building's roof, legs dangling over the edge as she closed her eyes, allowing the wind to blow around her.

 _This school is beautiful & I see why Mephisto stays around. Watching people grow, not only in age, but in knowledge._ Cheshire thought as she drew her sword, the lovely red flames engulfed her.

"You think a lot, don't you?" Amaimon asked as he sat besides her, suckers sticking out his coat's pocket.

Cheshire reclined back, "Yea, it's habit. I mean, being the daughter of Satan isn't something that happens to just anyone." Amaimon picked up on the sad tone of her voice, it was faint, but there.

"I don't understand why it is you think so often." He said, "I mean, yes you're related to Satan, but you're too... beautiful of a girl to worry about such things." Amaimon said with a blank expression. Cheshire looked at him in wonder.

 _Such an odd boy. Shows no emotions except a crazed, or a wicked side, or one that lusts for candy._ She thought staring at him. Amaimon didn't know her reason for watching him, so he just stared back.

"Are you going to the party with Mephisto & I?" Cheshire asked still keeping his eyes. Amaimon nodded, pale hand cupping the side of her face, his black nails grazing the skin beneath her vast brown eyes.

"Such a perfect demon, no wonder your flames are blue." He whispered as their lips grew closer, until they met briefly. A volt of electricity coursed through both of them, & they leaned back, Amaimon's hand now resting atop her own. He smiled, & Cheshire couldn't help bur smile back at him.

"You're such a dork." She chuckled.

Amaimon frowned, "I am no such thing." His childish voice coming through, "Oh, I must be going, but I'll see you at the party." He stood, pecking her lips before vanishing.

 

* * *

 

Mephisto's gaze flitzed to the door as it creaked slightly, Cheshire walked in, fingers gently brushing her lips before it went back to her side.

"I have your dress picked- what happened to you?" Mephisto asked, setting down his magazine. Cheshire was brought back to the present & she jumped slightly.

"What? What are you talking about Samael?" She asked quickly, cursing herself when her voice shook.

Mephisto clicked his tongue, "Something happened today, dazed look, zoning out, you look like you're floating on a cloud baby sister." She growled at the name.

"Don't call me that! And it is none of your business what I've gotten in to!" She said. Mephisto appeared behind her, reach around either side with a gloved hand, fingers danced along her neck, & collarbone aimlessly.

"Aye, it is my business." He said against her ears, "You are my sister after all, half or full, we're still related." His thin lips brushing against her sensitive ear with each word. Cheshire pushed him back, glaring halfheartedly at the purple haired demon.

"This will probably make you jelly..." she muttered before shrugging to herself, "Eh,   I don't really care I just realized; I kissed Amaimon." Cheshire said, tail flickering behind in as she waited for his reaction. He merely raised a brow, gloved hand resting on his cocked hip.

"I care why?" He asked. Cheshire stated back at him only slightly shocked.

"For a demon king, you aren't as territorial as I thought you'd be." She said avoiding his question. Mephisto let his hand fall from his hip & he sauntered over to her, placing both his hands on either side of her head.

"Believe me, I am," he said against her neck. "But Amaimon is merely a boy, he doesn't know of things such as this. I'll let him have his fun... for now." Mephisto pushed away from her but not before biting harshly at her collarbone, leaving a dark purplish mark on her caramel skin.

"Ugh," she groaned. "Anyways, where's my clothes for the party? I mean, it's almost six thirty." Mephisto gestured to his room, & Cheshire walked to the cracked door, feeling a little giddy at the excitement as she wondered what her older brother had chosen for her.

 _She would kiss Amaimon first, such an innocent boy. Probably didn't even understand himself what he did._ Mephisto thought as he finally got up from his chair, tucking his paper under his arm as he marched to the room.

"Mephisto, this is really awesome!" Cheshire squealed as she held the dress against her. She wasn't much of a dress girl, but she'd fallen for the dress Mephisto had chosen for her. It was a black halter neck rockabilly dress.

Mephisto bowed slightly, "Then put it on. We haven't much tome before we leave." He said tipping his hat before exiting the room.

 _I'm surprised he left,_ she thought smugly before undressing.

 

* * *

 

Mephisto turned around after speaking with the chauffeur, eyes widening & sparkling at the strut Cheshire did towards him.

"Oh, you actually have a pair of heels." He commented looking at her black high heels, adding three inches to her 5'7 height. Mephisto smiled & took her small hand into his, finding hers gloved as well. "And you have white gloves?" He asked pecking her hand.

Cheshire huffed, "Of course, I use to be a butler for some kid so I could steal his soul." She grinned deviously at the memory, "However, I must say he was quite enjoyable, annoying at times, but fin either way." They chuckled together & Mephisto led her to the limo, opening the door for her, "Thank you."

"You're welcome." He said sliding in besides her. They talked amongst themselves as their chauffeur drove, making the occasional left or right.

"I must say brother, I've never seen you look so good." Cheshire said taking her in brother's lithe frame fitted in a smug black dress suit, his black pointed shoes freshly polished, & instead of a tie he wore a red cravat, & his usually unruly hair was slicked down, except for a single curled hair atop his head.

"If I were to say the same about you, I'd be lying," he said reclining back against the leather seats, "For you my dear sister, look good all the time." Mephisto said smiling. Cheshire smiled back, feeling her cheeks grow warm at the compliment. The limo lurched to a stop, & the man dressed a suit opened the door & Mephisto stepped out, taking Cheshire by the hand.

"Thank you." She said appreciatively. Mephisto nodded as she hooked her arm with his, shaking her hair out of her face as they walked up the steps to the main entrance.

"Are you ready to be bored out your mind? All the compliments we receive & such will bore you quickly," he stated with a flat tone. Cheshire nudged him lightly.

"It can't be that bad, & I can't believe you of all people actually hate the attention of others." She said with a laugh.

"True, but I wish to only attract the attention of certain people," he replied slyly.

She snorted, "As if, you piss off the Vatican all the time. I wouldn't think anyone would want their attention, especially when the price is their head." Cheshire said causing Mephisto to grin.

"It's fun pushing their buttons, especially when I have you." He said giddy, "You'll kick their asses in a heartbeat with the way you hide your blue flames!" Mephisto said at they entered the party.

**Author's Note:**

> Tell me what you think ^-^


End file.
